Abstract-Routing layer is one of the most important layers of the network stack. In wireless ad hoc networks, it becomes more significant because nodes act as relay nodes or routers in the network. This characteristic puts them at risk of routing attacks. A wormhole is the most treacherous attack on a routing layer of wireless ad hoc networks. The present proposed techniques require extra hardware, clock synchronization; or they make restrict assumption to deal with this attack. We have proposed a simple behavior-based approach which uses a small amount of memory for recording a few packets received and sent by the neighboring nodes. From this information, a behavior of these nodes is detected, that is, whether the behavior is benign or malicious. Nodes exhibiting malicious behavior are placed in the blocked node list. Malicious nodes are broadcasted in the network. None of the legal nodes in the network entertains any packet from these nodes. This approach has been simulated and verified in ns2.30 which detects and isolates wormhole nodes successfully. The current study focuses on the looping behavior of this attack.